Ejector mechanism for mixer



SePt- 12, v1967 w. L.. CHAMBERS l-:TAL 3,341,181

EJECTOR MECHANISM FOR MIXER 3 Sheets-Sheet l Original Filed March 27,1964 7 6' J4' 30 INVENTORS: A

Spt 12, 1967 w. l.. CHAMBERS ETAL 3,341,181

EJECTOR MECHANISM FOR MIXER Original Filed March 27, 1964 3 Sheets-Sheetil.

We@ Q.

SePt- 12, 1967 w. l.. CHAMBERS ETAL 3,341,181

EJECTOR MECHANISM FOR MIXER Original Filed March 27, 1964 3 Sheets-Sheet2 474 526, 2.4 J0 20v H/ @O QQ 4-7/\` i? 69 70 @27/ 7j-zz` 72 5H" 75 675 United States Patent O 3,341,181 EJECTOR MECHANISM FOR MIXER Worthy L.Chambers, Wilmette, and James A. Wright,

Chicago, Ill., assignors to-Sunbeam Corporation, Chicago, Ill., acorporation of Illinois Original application Mar. 27, 1964, Ser. No.355,171, now Patent No. 3,271,013, dated Sept. 6, 1966. Divided and thisapplication Mar. 3, 1966, Ser. No. 531,388

2 Claims. (Cl. 259-1) ABSTRACT OF THE DISCLOSURE The open front end ofthe mixer base is closed by an L-shaped beater ejection lever which ispivoted to the mixer base. The base portion of the L-shaped beaterejection lever extends beneath the mixer base to above a pair ofshoulders on the mixer beater shafts. When the L-shaped lever is pivotedtowards the mixer its base portion bears down on the mixer beater shaftshoulders to disengage the mixer beater shafts from the mixer.

This invention relates to improvements in mixers, and more particularly,to an improved low -cost mixer. This application is a division of patentapplication Ser. No. 355,171, filed Mar. 27, 1964, and now Patent No.3,271,013.

It is an object of this invention to provide a low cost, readilyassembled, and improved mixer.

Heretofore, it has been common to mount the mixer parts such as themotor, its bearings, the commutator brushes, their insulation, and thedrive mechanism for the beaters on a metal base member such as a diecasting. This die cast base member had to be machined or finished toproper dimensions to 'accurately mount the mixer parts. The base memberand assembled mixer was enclosed in an outer casing or housing. Theouter housing commonly comprised two complementary molded plasticmembers which together defined an enclosure for the mixer and its basemember. These two plastic members commonly cornprised a bottom memberand 'a top member having a handle integrally formed thereon or otherwiseconnected thereto.

The requirement of a die cast base member and its machining or finishingobviously added to the cost of the mixer. This was true even if thebottom plastic member was omitted. That is to say, high costs were theresult even if the die cast base member also served as a bottom closuremember. Metal base members, for one thing, were thought to be necessaryto obtain adequate cooling of the motors. Stated another way, it wasbelieved to be impractical to use molded plastic for the base member,because of the problems of rapidly -dissipating the heat generated bythe moving mixer parts or overheating of' the plastic.

Briefly, in the invention a single molded plastic part, such asphenolic, is used as a base member and bottom closure member for themixer. Using molded plastic makes it possible to readily form thenecessary supports or recesses for the mixer parts without furtheroperations such as machining. Using molded plastic also makes itpossible to eliminate certain electrical insulating parts which wereheretofore required with metallic `die cast base members. The beaterspindle bearings are integrally formed in the molded plastic mixer base.The beater spindles and their gears are also integrally formed with eachother from molded plastic such as nylon. The seats for the bearings andfthe holders for the commutator brushes are integrally formed in theplastic base member. All these illustrative parts can be accuratelyformed by known molding processes making special inserts or the ice ingfins. The cooling fan is constructed from aluminum,

for example, for a similar purpose. The bracket for supporting the mixerswitch is likewise constructed from aluminum and is mounted on the frontbearing retainer. The -cumulative effect of these steps is to insure'adequate cooling so that the plastic base member is not overheate-d.For example, the aluminum fan, cooling iins on the front bearing, andthe aluminum strap for the switch insure proper cooling of the front endof the mixer. The front end of the mixer contains the commutator 'andthe brushes and the -beater spindle drive mechanism which is an area ofhigh heat generation due to the friction of these moving parts.

Additionally, in the invention a single piece beater ejector isprovided. The beater ejector comprises a generally L-shaped member whichcloses the front end and front bottom portion of a mixer housing whichis open in front and below the bearings for the beater shafts. Thebeater shafts have shoulders formed thereon below the bearings. The baseof the L-shaped member acts downwardly on the shoulders to eject theshafts and it also closes the open front bottom portion of the housing.The other part of the L-shaped member closes the front end of thehousing and is pivotally connected to the housing in an uncomplicatedmanner by integral bearing means formed on the housing and L-shapedmember and a spring.

The switch of the mixer is mounted in the hollow post of the mixerhandle by inserting it through the bottom of the post. The switchcomprises a terminal board and two of its opposite edges are received ina pair of grooves formed in opposite sides of fthe hollow post. Theupper end of the board has a projection formed thereon along one of thementioned edges. The end of the groove corresponding to this edgeterminates in a notch adapted to receive the projection.

The invention will be better understood by considering the followingdescription taken in connection with the accompanying drawings.

In the drawings, FIG. 1 is a perspective view of a mixer embodying theinvention;

FIG. 2 is an enlarged sectional View taken along the section line 2 2 ofFIG. l;

FIG, 3 is a sectional view taken along the section line 3 3 of FIG. 2;

FIG. 4 is a top plan view of the mixer with the upper portion of thehousing removed;

FIG. 5 is a broken away sectional View similar to that of FIG. 2 showingthe beater ejection mechanism in ejecting position;

FIG. 6 is a broken away section view taken along the section line 6 6 ofFIG. 2;

FIG. 7 is an enlarged sectional View taken along the section line 7 7 ofFIG. 4;

FIG. 8 is a sectional View taken along the section line 8 8 of FIG. 7;

FIG. 9 is an enlarged sectional view taken along the section line 9 9 ofFIG. 4;

FIG. 10 is a sectional view similar to that of FIG. 7 showing 'amodification `of the spindle bearing; and

FIG. 11 is an exploded perspective View of the improved brush assembly.

Referring now to the drawings, a hand type mixer is illustrated and itscomprises a housing or casing having top and bottom or base members 10Iand 11 respectively. Members 10 and 11 are recessed and elongated. Ahandle or hand grip 12 is conne-cted to the mixer by a hollow post 13.Post 13 may be integral with handle 12 Iand top member 10. The workingparts of the mixer are assembled in the bottom member 11, and the topmember comprises a cover for the bottom member 11 and its supportedparts. Both members 10 and 11 are fabricated from molded plastic.

The mixer comprises a motor having a stator core 14 and thestatorwindings 15. The stator core 14 is supported on integral ledges 16 `ofthe base or bottom member 11 by positioning screws 17. The shaft 18 ofthe motor armature 19 is supported in front and rear bearings 20 and 21,respectively, see FIG. 2. The bearings 20 and 21 are supported inintegral bearing supports 22 and 23, respectively, of the base member11. The bearings 20 and 21 are retained on the supports 22 and 23 bybearing retainers 24 and 25 respectively. Bearing retainers 24 and 25are held in place by screws or the like 26 and are provided withintegral cooling ns 24 and 25 respectively.

The armature 19 is provided with a commutator 27 and commutator brushes28. Brushes 28 are guided in recessed brush holders 29 which are formedintegral with base 11. The brushes 28 are retained captive in the brushholders 29 by brush retainers 30 and screws or the like 31. The brushretainers 30 are shaped the same and are reversible left for right. Anend thrust bearing 32 is provided for the rear of shaft 18, and a fanblade 33 mounted on shaft 18 pulls a cooling draft through the housing.Suitable cooling air vents are provided in the housing in a manner wellknown to those skilled in the art. The fan 33 is preferably constructedfrom aluminum to dissipate heat, and the bearing retainers 24 and 25from copper alloy.

The end thrust bearing pad 32 is held captive in an integral recessedportion 11' of the base 11, see FIG. 4. An electric extension cord 60enters the housing through an aperture 61 formed in the rear portion ofbase 11. A strain relief for cord 60 is integrally formed on base 11.The strain relief comprises a pair of spaced lugs 62 and 63 integralwith base 11 adjacent aperture 61. The cord 60 after passing throughaperture 61 is curved first around lug 62. Then it extends between lugs62 and 63 and curves around lug 63. This snaking or curving of cord 60around and between the lugs 62 and 63 relieves the stress on the innerconnection, not illustrated, of the cord 60 to the motor.

Referring to FIG. 9, the screws 17 mount the stator 14 by clamping itsintegral shoulders 14 to the ledges 16 of base 11. Outboard of theledges 16 the base 11 has integral shoulders 64 beneath the heads of thescrews 17. Shoulders 64 prevent the screws 17 from cocking in anoutboard direction when they are tightened. As screws 17 are inallytightened they will engage the shoulders 64. In the absence of shoulders64 tightening of screws 17 would result in their tilting or cocking awayfrom the stator, and this movement would develop cracks or weaknesses inthe plastic base at the area of the screws.

The plastic `of base 11 gives double insulation characteristics to themixer. For example, if a fault should develop in the insulation ofstator windings 15, since base 11 is constructed from plastic therewould not be a short circuit through the base, which would be the caseif base 11 were a metallic die casting. The plastic base 11 also makesit possible to economize on insulation inserts required with die castbases. For example, if the brush holders or guides 29 were integrallyformed in a metallic die casting then insulating sleeves would berequired for the brushes 28.

Ahead of the front motor bearing support 22, a pair of spindle ybearings34 are formed integral with base 11. Bearings 34 are hollow and havetheir axes disposed perpendicular to the lengthwise axis of base 11. Thebearings 34 have hollow beater shaft receiving spindles 35 insertedtherein, see FIG. 7. Pinion gears 35 are integrally formed at the upperend of the hollow spindles 35, and these gears 35 are driven by a pinionworm 36 formed at the forward end of shaft 18. The integral spindles 35and gears 35 are constructed from plastic such as graphite impregnatedor molybdenum disulphide compounded nylon. The nylon spindles 35 ridedirectly on the phenolic of bearings 34 and the graphite or molybdenumdisulphide serves as a lubricant making an enclosed gear chamber andgrease unnecessary.

A pair of beater shafts 37 are received in the bearings 34 and removablylocked in their hollow spindles 35 for manual ejection in a manner to bedescribed. The bearings 34 and spindles 35 have a slight draft angle ortaper to facilitate their fabrication by molding and subsequent assemblywithout holding close manufacturing tolerances. That is to say, theinner bearing surface of bearing 34 and the outer bearing surface ofspindle 35 have a slight cone-shape. Also, the bearing 34 is slightlylarger than the spindle 35. Therefore, when spindle 35 is inserted intobearing 34, the upper end of bearing 34 will engage the underside ofgear 35. Therefore, bearing support is provided for the spindle properas well as its integral gear. This is illustrated in FIG. 7. Themodification shown in FIG. 10 is the same except that distinct upper andlower bearing surfaces or lands are formed at the A and C areas of thebearing 34. In this form of the invention the distinct upper and lowerbearings are formed at the same taper, but the area B is relieved byhaving a larger taper or draft angle. This arrangement will nd advantagein the case of long spindles, such as those required in more powerfulstandtype mixers. Otherwise, the FIGS. 7 and 10 forms of the inventionare the same. Distinct A and C bearing lands and the intervening reliefB are useful in large stand type mixers since with long molded spindlesit may be diicult to compensate for surface molding irregularities.

The shafts 37 are axially retained in the spindles 35 by a split oneturn locking spring 65. Spring 65 is loosely carried by shaft 37 in agroove 66. When shaft 37 is inserted into spindle 35 spring 65 is rstcompressed into groove 66 and then free to expand into a groove 67 whengrooves 66 and 67 are aligned. The groove 67 is formed on the lower endof the spindle 35. The annular ridge 68 just below groove 67 is the partof spindle 35 which compresses the ring 65 into groove 66 when insertingor removing the shaft 37.

The drive connection between the shaft 37 and spindle 35 comprises axialkeys 69 on the shaft 37 which enter axial key receiving grooves 70formed on the inside of the hollow spindle. The grooves 70 are notthrough slots. If they were, this would be an area of weakness in thespindle 35. Since the grooves 70 are not through slots the grooves 70 ineffect are interconnected by integral web portions 71 of the lower endof the spindle. To look at it another way, if grooves 70 were throughslots the webs 71 would in effect be spaced drive fingers for receivingthe keys 69. Such spaced drive fingers, when constructed from plastic,might fracture or become mutilated. Therefore, an outer reinforcingring, such as of metal, would have to be used for the fingers. However,with the integral webs 71 no reinforcing ring is required to obtain adrive connection which is adequate to do the job and long lived.

The spindles 35 are retained in the bearings 34 by means such as bearingand lock washers 72 and 73 positioned on the lower end of spindles 35.The shafts 37 have shoulders 38 formed thereon beneath the bearings 34for purposes of ejecting the shafts 37. The front end of base member 11is open or cut away below and ahead of the bearings 34. This opening isclosed by a one-piece beater ejector member 39. Member 39 is generallyL-shaped with its base portion 39' normally disposed between bearings 34and shoulders 38. The other portion 39" of L-shaped member 39 ispositioned in front of bearings 34 and integral pivot bearing means 40and 41 are formed on the bearings 34 and inside of portion 39". Thepivot bearing portions 40 and 41 are retained engaged by a coil spring42. The axis of coil spring 42 is disposed beneath pivot bearing means40, 41 and spring 42 biases the beater ejector 39 to the non-ejectingposition illustrated in FIG. 2. To eject the beaters, it is merelynecessary to push its upper end or ejector button portion 43 inwardly asillustrated in FIG. 5. The base portion 39' has two notches 43' whichare aligned with the spindles 35 through which the shafts 37 can beinserted into the spindles 35. The coil spring 42 extends from theinside of L-shaped member 39 to the upper part of a wall 44 integralwith base 11. Wall 44 extends between bearings 34 and is also integraltherewith.

The speed of the mixer is controlled by a switch indicated generally byreference numeral 50. Switch 50 comprises a terminal switch board 51which is inserted into the hollow post 13 through the bottom thereof.The switch includes an operating lever 52 protruding through the top ofpost 13. The upper end of lever 52 has a thumb knob 53. The front andrear edges of the board 51 are received in front and rear grooves 54 and55 formed inside the hollow post 13. Formed on the top of board 51 alongits front edge is projection 56 which is preferably Wedgeshaped. Thisprojection is received in an inverted V-shaped notch 57 formed at theupper end of groove 54. The board 51 is supported in the grooves 54, 55and notch 57 from its lower end by a rigid support strap 58. At itsupper end the strap 58 is connected to the board 51 and at its lower endstrap 58 is mounted on the front bearing support 22 by one of the screws26. Strap 5S is preferably constructed from aluminum for heatdissipating purposes.

The mixer is assembled as illustrated in the drawings on the base member11., Thereafter the top part is placed over member 11 to insert theboard 51 in its grooves 54, 55 and notch S7. In this position of cover10, lever 52 will protrude through the upper end of post 13. Thereafter,the assembly is completed as by screws 59 connecting members 10 and 11together and the addition of knob 53 to lever 52.

The improved commutator brush assembly Will now be described byreference to FIGS. 4 and 11. The brush holders 29 are integrally formedin the plastic base member 11 and seat the brushes 28 directly on theplastic base. 'Ihe brush holders 29 have a channel or guideway 70 whichis slightly oversize with respect to the cross section of the brushes sothat they are free to slide toward the commutator 27 as they wear.Brushes 28 are biased inwardly by coil springs 71 disposed behind thebrushes. The brush retainers 30 are L-shaped and are superposed on thebrush holders to close the open upper sides of channels 70. Thehorizontal leg 30 of the retainers extend lengthwise of channel 70whereas the vertical leg 30 closes the outer open ends of the channel70. One side of the brush holders 29 have an integral boss 29' forreceiving the screw 31. The other side has integral spaced positioningprojections or lugs 29". A notch 72 is formed on opposite sides of thelegs 30. These notches pass the screws 31. Each notch 72 is bounded by apair of tabs 73 which fit between the positioning lugs 29". A pair oflugs 29" are also formed at the outer end of brush holders 29 alongopposite sides of the channel 70. These lugs engage the bottom edge ofthe lug 30". The coil springs 71 are trapped inside the channel 70between the brushes 28 and legs 30". A lead 74 is soldered to the legs30 and current flows from the brush to the lead through the retainers 30and springs 71. With this construction the brushes are easy to replace,the assembly is low cost, and no special inserts are required. Forexample, the base 11 itself provides the necessary insulation for thebrushes, thereby eliminating the prior art insulating sleeves or brushholders of prior mixers using die cast bases.

While there has been illustrated and described an embodiment of thepresent invention, it will be appreciated that numerous changes andmodifications will occur to those skilled in the art, and it is intendedin the appended claims to cover all those changes and modifications asfall within the true spirit and scope of the present invention.

What is claimed as new and desired to be secured by Letters Patent ofthe United States is:

1. In a hand mixer, a casing comprising an elongated recessed lowerhousing member, a pair of hollow bearings integrally formed on saidhousing member adjacent the front end thereof, said bearings beingdisposed perpendicular to the lengthwise axis of said housing member,said front end and the bottom portion of said housing member adjacentsaid front end being open to expose the front and bottom of saidbearings, a pair of beater shafts positioned in said bearings, ashoulder formed on said shafts beneath said bearings, a one-piece memberfor ejecting said beater shafts and closing said open bottom portion andfront end, said one piece member being generally L-shaped, the baseportion of said L-shaped member being positioned in said open bottomportion between said bearings and shoulders, and the other portion ofsaid L-shaped member being positioned ahead of said bearings, engageablepivot bearing means integrally formed on said housing member and saidL-shaped member for pivotally mounting said L-shaped member on saidhousing member, and a spring interconnecting said housing member andL-shaped member, said spring retaining said pivot bearing means engagedand biasing said L-shaped member to non-ejecting position.

2. In a hand mixer as in claim 1, wherein said pivot bearing means areformed on said bearings and the inside of said other portion of saidL-shaped member, a Wall integral with said housing member extendingbetween said bearings, and said spring comprising a coil spring,opposite ends of said coil spring being connected to said wall and theinside of said L-shaped member, and the axis of said coil spring beingdisposed beneath said pivot bearing means.

References Cited UNITED STATES PATENTS 3,275,051 9/1966 Jepson et al.259-131 X 3,280,351 10/1966 Wolter et al 259-131 X FOREIGN PATENTS602,050 7/ 1960 Canada. 1,261,027 4/1961 France.

WILLIAM I. PRICE, Primary Examiner.

1. IN A HAND MIXER, A CASING COMPRISING AN ELONGATED RECESSED LOWERHOUSING MEMBER, A PAIR OF HOLLOW BEARINGS INTEGRALLY FORMED ON SAIDHOUSING MEMBER ADJACENT THE FRONT END THEREOF, SAID BEARINGS BEINGDISPOSED PERPENDICULAR TO THE LENGTHWISE AXIS OF SAID HOUSING MEMBER,SAID FRONT END AND THE BOTTOM PORTION OF SAID HOUSING MEMBER ADJACENTSAID FRONT END BEING OPEN TO EXPOSE THE FRONT AND BOTTOM OF SAIDBEARINGS, A PAIR OF BEATER SHAFTS POSITIONED IN SAID BEARINGS, ASHOULDER FORMED ON SAID SHAFTS BENEATH SAID BEARINGS, A ONE-PIECE MEMBERFOR EJECTING SAID BEATER SHAFTS AND CLOSING SAID OPEN BOTTOM PORTION ANDFRONT END, SAID ONE PIECE MEMBER BEING GENERALLY L-SHAPED, THE BASEPORTION OF SAID L-SHAPED MEMBER BEING POSITIONED IN SAID OPEN BOTTOMPORTION BETWEEN SAID BEARINGS AND SHOULDERS, AND THE OTHER PORTION OFSAID L-SHAPED MEMBER BEING POSITIONED AHEAD OF SAID BEARINGS, ENGAGEABLEPIVOT BEARING MEANS INTEGRALLY FORMED ON SAID HOUSING MEMBER AND SAIDL-SHAPED MEMBER FOR PIVOTALLY MOUNTING SAID L-SHAPED MEMBER ON SAIDHOUSING MEMBER, AND A SPRING INTERCONNECTING SAID HOUSING MEMBER ANDL-SHAPED MEMBER, SAID SPRING RETAINING SAID PIVOT BEARING MEANS ENGAGEDAND BIASING SAID L-SHAPED MEMBER TO NON-EJECTING POSITION.